When troops arrived in 1852 to establish this post, it was first called Camp San Saba because it overlooks the headwaters of the San Saba River Valley. It was established by five companies of the Eighth Infantry in March, 1852 to protect frontier settlers and travelers on upper San Antonio-El Paso Road.

It was renamed Fort McKavett, in honor of Captain Henry McKavett, who was killed in the Battle of Monterey during the Mexican-American War. The fort was garrisoned with 350-500 troops, about half of which were infantry, the rest from cavalry companies, and officers that served in the regimental headquarters. When the post was complete, General William T. Sherman would describe it as "the prettiest post in Texas."